diff --git a/packages/core/src/dependency-injector.ts b/packages/core/src/dependency-injector.ts
index b695f05..31cf059 100644
--- a/packages/core/src/dependency-injector.ts
+++ b/packages/core/src/dependency-injector.ts
@@ -1,5 +1,5 @@
 import assert from 'assert';
-import { awaitAllEntries, isPlainObject, mapObject } from '@stilt/util';
+import { awaitMapAllEntries, isPlainObject, FORCE_SEQUENTIAL_MODULE_IMPORT } from '@stilt/util';
 import type { Factory } from './factory';
 import { isFactory } from './factory.js';
 import type { TOptionalLazy } from './lazy';
@@ -65,6 +65,7 @@ export default class DependencyInjector {
       // dependencies: { myService: lazy(() => MyService) }
       | { [key: string]: TOptionalLazy<TInstantiable<T>> },
   ): Promise<T | T[] | { [key: string]: T }> {
+    // @ts-expect-error
     return this._getInstances(moduleFactory, []);
   }
 
@@ -88,21 +89,17 @@ export default class DependencyInjector {
       return this._getInstance<T>(moduleFactory, dependencyChain);
     }
 
-    if (Array.isArray(moduleFactory)) {
-      return Promise.all(
-        moduleFactory.map(async ClassItem => this._getInstance(ClassItem, dependencyChain)),
-      );
-    }
-
-    if (typeof moduleFactory === 'object' && isPlainObject(moduleFactory)) {
-      return awaitAllEntries(mapObject(moduleFactory, async (aClass: TOptionalLazy<TInstantiable<T>>, key: string) => {
+    if (Array.isArray(moduleFactory) || typeof moduleFactory === 'object' && isPlainObject(moduleFactory)) {
+      // @ts-expect-error
+      return awaitMapAllEntries(moduleFactory, async (ClassItem, key) => {
         try {
-          return await this._getInstance<T>(aClass, dependencyChain);
+          // @ts-expect-error
+          return await this._getInstance<T>(ClassItem, dependencyChain);
         } catch (e) {
-          // TODO: use .causedBy
+          // TODO: use { cause: e }
           throw new Error(`Failed to build ${key}: \n ${e.message}`);
         }
-      }));
+      }, FORCE_SEQUENTIAL_MODULE_IMPORT);
     }
 
     assert(typeof moduleFactory === 'function');
diff --git a/packages/graphql/src/index.ts b/packages/graphql/src/index.ts
index f0f8c00..83e0274 100644
--- a/packages/graphql/src/index.ts
+++ b/packages/graphql/src/index.ts
@@ -3,7 +3,7 @@ import path from 'path';
 import type { InjectableIdentifier, TRunnable } from '@stilt/core';
 import { App, factory, isRunnable, runnable } from '@stilt/core';
 import { StiltHttp } from '@stilt/http';
-import { asyncGlob, coalesce } from '@stilt/util';
+import { asyncGlob, awaitMapAllEntries, coalesce, FORCE_SEQUENTIAL_MODULE_IMPORT } from '@stilt/util';
 import type {
   GraphQLNamedType,
   Source, DocumentNode,
@@ -207,7 +207,7 @@ export class StiltGraphQl {
      * - A GraphQL type (eg. a GraphQL enum, any export)
      */
 
-    const resolverExports = await Promise.all(resolverFiles.map(readOrRequireFile));
+    const resolverExports = await awaitMapAllEntries(resolverFiles, readOrRequireFile, FORCE_SEQUENTIAL_MODULE_IMPORT);
 
     const resolverInstancePromises = [];
     for (const resolverExport of resolverExports) {
diff --git a/packages/rest/src/index.ts b/packages/rest/src/index.ts
index b5124a4..115dcc3 100644
--- a/packages/rest/src/index.ts
+++ b/packages/rest/src/index.ts
@@ -3,7 +3,7 @@ import { App, factory, isRunnable, runnable } from '@stilt/core';
 import type { Class } from '@stilt/core/types/typing';
 import { StiltHttp } from '@stilt/http';
 import { wrapControllerWithInjectors } from '@stilt/http/dist/controllerInjectors.js';
-import { asyncGlob } from '@stilt/util';
+import { asyncGlob, awaitMapAllEntries, FORCE_SEQUENTIAL_MODULE_IMPORT } from '@stilt/util';
 import { getRoutingMetadata } from './HttpMethodsDecorators.js';
 import { IsRestError } from './RestError.js';
 
@@ -145,28 +145,24 @@ export class StiltRest {
   private static async loadControllers(app: App, schemaGlob: string) {
     const controllers = await asyncGlob(schemaGlob);
 
-    const apiClasses = (await Promise.all(
-      Object.values(controllers).map(async controllerPath => {
-        const controllerModule = await import(controllerPath);
-        const controllerClass = controllerModule.default;
+    const apiClasses = (await awaitMapAllEntries(Object.values(controllers), async controllerPath => {
+      const controllerModule = await import(controllerPath);
+      const controllerClass = controllerModule.default;
 
-        if (controllerClass == null || (typeof controllerClass !== 'function' && typeof controllerClass !== 'object')) {
-          return null;
-        }
+      if (controllerClass == null || (typeof controllerClass !== 'function' && typeof controllerClass !== 'object')) {
+        return null;
+      }
 
-        return controllerClass;
-      }),
-    )).filter(controllerClass => controllerClass != null);
+      return controllerClass;
+    }, FORCE_SEQUENTIAL_MODULE_IMPORT)).filter(controllerClass => controllerClass != null);
 
-    const apiInstances = await Promise.all(
-      apiClasses.map(async resolverClass => {
-        if (typeof resolverClass === 'function') {
-          return app.instantiate(resolverClass);
-        }
+    const apiInstances = (await awaitMapAllEntries(apiClasses, async resolverClass => {
+      if (typeof resolverClass === 'function') {
+        return app.instantiate(resolverClass);
+      }
 
-        return null;
-      }),
-    );
+      return null;
+    }, FORCE_SEQUENTIAL_MODULE_IMPORT)).filter(controllerInstance => controllerInstance != null);
 
     const routeHandlers = [...apiClasses, ...apiInstances];
 
diff --git a/packages/util/src/index.ts b/packages/util/src/index.ts
index 2532c39..014a35f 100644
--- a/packages/util/src/index.ts
+++ b/packages/util/src/index.ts
@@ -10,7 +10,7 @@ export function hasOwnProperty<X extends {}, Y extends PropertyKey>(
   return Object.prototype.hasOwnProperty.call(obj, propertyKey);
 }
 
-export function isPlainObject(obj: any): obj is Object {
+export function isPlainObject(obj: any): obj is object {
   const proto = Object.getPrototypeOf(obj);
 
   return proto == null || proto === Object.prototype;
@@ -56,9 +56,16 @@ export function coalesce<T>(...args: T[]): T {
 }
 
 type UnwrapPromise<T> = T extends Promise<infer U> ? U : T;
-
-export async function awaitAllEntries<T extends { [key: string]: any },
-  >(obj: T): Promise<{ [P in keyof T]: UnwrapPromise<T[P]> }> {
+type MaybePromise<T> = Promise<T> | T;
+
+// eslint-disable-next-line max-len
+export async function awaitAllEntries<In, T extends { [key: string]: MaybePromise<In> }>(obj: T): Promise<{ [P in keyof T]: UnwrapPromise<T[P]> }>;
+export async function awaitAllEntries<In>(obj: Array<MaybePromise<In>>): Promise<In[]>;
+// eslint-disable-next-line max-len
+export async function awaitAllEntries<In, T extends ({ [key: string]: MaybePromise<In> })>(obj: T | Array<MaybePromise<In>>): Promise<{ [P in keyof T]: UnwrapPromise<T[P]> } | In[]> {
+  if (Array.isArray(obj)) {
+    return Promise.all(obj);
+  }
 
   const values = await Promise.all(Object.values(obj));
   const keys = Object.keys(obj);
@@ -73,7 +80,7 @@ export async function awaitAllEntries<T extends { [key: string]: any },
   return resolvedObject;
 }
 
-export function mapObject<In, Out, T extends { [key: string]: In }>(
+export function mapObject<In, Out, T>(
   obj: T,
   callback: (value: In, key: string) => Out,
 ): { [P in keyof T]: Out } {
@@ -88,6 +95,71 @@ export function mapObject<In, Out, T extends { [key: string]: In }>(
   return newObject;
 }
 
+export function mapEntries<In, Out, T extends { [key: string]: In }>(
+  obj: T,
+  callback: (value: In, key: string | number) => Out
+): { [P in keyof T]: Out };
+
+export function mapEntries<In, Out>(
+  obj: In[],
+  callback: (value: In, key: string | number) => Out
+): Out[];
+
+export function mapEntries<In, Out, T extends ({ [key: string]: In })>(
+  obj: T | In[],
+  callback: (value: In, key: string | number) => Out): { [P in keyof T]: Out } | Out[] {
+  // process.env.JEST_WORKER_ID
+  if (Array.isArray(obj)) {
+    return obj.map((value, key) => callback(value, key));
+  }
+
+  return mapObject(obj, callback);
+}
+
+// eslint-disable-next-line max-len
+export async function awaitMapAllEntries<In, Out, T extends { [key: string]: In }>(obj: T, callback: (value: In, key: string | number) => MaybePromise<Out>, sequential?: boolean): Promise<{ [P in keyof T]: Out }>;
+// eslint-disable-next-line max-len
+export async function awaitMapAllEntries<In, Out>(obj: In[], callback: (value: In, key: string | number) => MaybePromise<Out>, sequential?: boolean): Promise<Out[]>;
+// eslint-disable-next-line max-len
+export async function awaitMapAllEntries<In, Out, T extends ({ [key: string]: In })>(
+  obj: T | In[],
+  callback: (value: In, key: string | number) => MaybePromise<Out>,
+  sequential?: boolean): Promise<{ [P in keyof T]: Out } | Out[]> {
+
+  // `sequential` option is a workaround due to a bug when using Jest with native ES Modules
+  // See https://github.com/facebook/jest/issues/11434
+  if (sequential) {
+    if (Array.isArray(obj)) {
+      const out = [];
+
+      for (let i = 0; i < obj.length; i++){
+        // eslint-disable-next-line no-await-in-loop
+        out.push(await callback(obj[i], i));
+      }
+
+      return out;
+    }
+
+    const out = {};
+    for (const key of Object.keys(obj)) {
+      // eslint-disable-next-line no-await-in-loop
+      out[key] = await callback(obj[key], key);
+    }
+
+    // @ts-expect-error
+    return out;
+  }
+
+  // @ts-expect-error
+  const mapped = mapEntries(obj, callback);
+  const out = awaitAllEntries(mapped);
+
+  // @ts-expect-error
+  return out;
+}
+
 export function assertIsFunction(item: any): asserts item is Function {
   assert(typeof item === 'function');
 }
+
+export const FORCE_SEQUENTIAL_MODULE_IMPORT = process.env.JEST_WORKER_ID != null;